单链表类及其实现设计单链表类，

实现构造、析构、插入、删除等基本的成员函数，并添加将单链表逆置、搜索值为x的成员函数-Design and realization of single-class single-linked list class that implements constructed, destructors, insert, delete, member of the basic functions, and add to the list against a single set, a member of the search function is x